The present invention relates to reusable boxes for packaging and containing cassette tape cartridges and particularly to a self-locking cassette box of the squeeze releasable type.
Available boxes for cassette tapes have been provided with a releasably openable feature. However, the desirability of providing means to securely retain the cassette tape in the cassette tape box has usually made it necessary to provide specific structure hinged to the box for this purpose. The cited requirement has resulted in prior art cassette tape boxes which are expensive to manufacture and cumbersome to use.
U.S. Pat. No. 3,912,077 discloses a cassette box having a locking cover which releasably unlatches by squeezing the front and back walls of the box. The tape cassette is pushed out of this box by springs attached to a bottom wall. The need to have a hinged cover to lock the cassette tape in however significantly adds to the complexity of the structure and requires that it made of non-flexing members interconnected by devices of specific functions such as hinges and springs. Squeezing is also used to remove a locking cover in U.S. Pat. No. 3,532,211 but is only achieved by using a complex structure.
The concept of locking a cassette tape in a cassette tape box by engaging a discontinuity on the cassette tape cartridge such as shoulder opening or projection appears to be used in U.S. Pat. Nos. 3,644,492; 3,994,551; 3,995,921; 3,909,088; 3,754,639; and 3,272,325. In each of these prior art boxes however, substantial additional structure distinct from the structure of the box itself is required for perform the locking function. Moreover, dexterity is required to release the locking mechanism in these prior art structures.